positive pressure ventilation may result in
decreased BP and decreased CO
need oxygen to break down ___
glucose
auto peep indicates
air trapping
are alveoli normally positive or negative during inspiration
positive
intrapleural pressure
pressure in the pleural space between parietal and visceral pleura
alveolar pressure (P a)
lung/intraplural pressure
normal alveolar pressure
-1 on inspiration and +1 on expiration
transairway pressure
pressure gradient between AW opening and alveolus
transthoracic pressure
pressure needed to expand or contract the lungs and chest wall at the same time
transpulmonary pressure also called
alveolar distending pressure
transpulmonary pressure
the pressure that maintains alveolar inflation
how is transpulmonary pressure effected by mechanical ventilation
increases
transrespiratory pressure
pressure required to inflate the lungs and airways during positive pressure ventilation
compliance equation
change in volume/change in pressure
normal compliance
.1 L/cmH20
normal compliance of an unintubated pt
.05- .17 L/cmh20
normal compliance of an intubated male pt
40-50 ml/cmh20
a pt with decreased lung compliance needs more ___ to get air into their lungs
pressure
ex of diseases that cause pts to have decreased lung compliance
ARDS, sarcoidosis, restrictive diseases
ex of a disease with increased lung compliance
emphysema
normal Raw
.6-2.4 cmH20/lps
normal raw of an intubated pt
6cm H20/lps
Raw increases as ETT ____
decreases
time constant is the product of
compliance and resistance
time constant is the
time required to fill/empty the lungs
how many time constants to completely fill the lungs
5
negative pressure ventilation disadvantage in
hypovolemic pts
when is plateau pressure measured
after inspiration before expiration
1mmhg = ____ cmh20
1.36
1kPa = ____mmhg
7.5
positive pressure ventilation can cause pressures on the heart resulting in
decreased BP and CO
open loop system
unintelligent" cant respond to changing conditions when delivering a Vt
closed loop system
intelligent" can respond to changes and compensate for problems with delivered Vt
MMV
minimal/mandatory ventilation. you set a minute ventilation and RR or Vt increases if Ve is not enough
the more Ti you have the more ___ you can get in
volume
phase variables
trigger variable, limit variable, cycle variable
cycle variable
ends inspiration
breath triggering by
time triggering, pressure triggering, flow triggering, volume triggering
time triggering is only for patients breathing
mandatory breaths
limit variables is the
maximum value a variable can attain
the 4 limit variables
pressure,volume,flow,time
the 4 cycle variables
pressure,vol,flow,time
does limit variable stop inspiration
NO
in volume control ___ ends inspiration
volume
in pressure control ____ ends inspiration
flow
on volume control if the PIP PLAT and MAP are too high what should you do
put pt on pressure control
if your using FLOLAN what triggering should you use
pressure triggering, bc of continuous nebulization
tubing compressability, vent tubing circuits lose about
2-3 ml of Vt for ever 1 cmh20 of PIP
you can tell if the system has a leak if the exhaled Vt is
less then the set volume (by 100)
ways to increase MAP pressure
increase PEEP, CPAP, RR, VT, Ti, Pressure support
CPAP
increased baseline pressure for spontaneously breathing pts
an increase in temperature and metabolism =
increase in co2 production and o2 consumption
is o2 or co2 effected first
02
how to recognize respiratory distress
level of consciousness, appearance, vitals
acute respiratory failure numbers
pao2-below normal for age
paco2- 50 and increasing
ph- 7.25 and lower
acute hypoxic respiratory failure
tissue hypoxemia (bad o2)
early signs of acute hypoxic respiratory failure
inc RR and inc HR
acute hypercapnic respiratory failure
co2 is bad PUMP FAILURE
causes of hypoxic respiratory failure
right to left shunting, alveolar hypoventilation, aging, inadequate o2 inspired
causes of hypercapnic resp failure (pump failure)
respiratory muscles, thoracic cage, and nerve damage
as co2 increase ____ increases
intracranial pressure
as o2 decreases hr ___
increases
refractory hypoxemia is caused by
shunting
combined effects of hypoxia, hypercapnia, and acidosis
ventricular arrest, fibrillation
how does a central nervous system disorder effect Ve and alveolar ventilation
Ve and alveolar vent decrease and more dead space
how does an ETT effect deadspace
decreases it
acceptable MEP
40 cmh20
minute ventilation is directly related to
metabolic rate
tobin index
RR/Vt
increased paco2 also indicates increased ____
physiological dead space
normal dead space
30-40 %
when the Pao2 is low and the P(A-a) is high hypoxemia is due to
shunting, diffusion defects, or V/Q mismatching
vapotherm
high flow of o2, creates PEEP and washes out deadspace